Many local governments provide solid waste services to their communities, including collection, transportation, management of recycling/composting programs, and management of landfills. This section of the LGOP provides guidance on estimating only the Scope 1 fugitive CH4 emissions released from landfills that contain organic waste. Other sections of the LGOP should be used to calculate emissions from other activities related to solid waste (e.g., electricity use, stationary combustion, and vehicle fleet).
This protocol applies only to those local governments that have operational or financial control over a landfills. Local governments that contract with third parties do not have operational or financial control, and so have the option of either not addressing such emissions, or of quantifying and reporting them as Scope 3 emissions.
Chapter 9 of the LGOP provides four different methodologies for estimating CH4 fugitive emissions from landfills, depending on the type of landfill gas (LFG) collection system that is in place:
Landfills with no LFG collection system (Chapter 9.3.1)
- Determine the annual waste deposited in the landfill historically.
- Input data into the Excel-based First Order Decay (FOD) model (downloadable at www.arb.ca.gov/cc/protocols/localgov /localgov.htm). Below are the facility-specific data that will be needed to provide the local government’s landfill in order to run the FOD model:
If a local government’s landfill does not have a LFG collection system in place, the LGO Protocol provides detailed steps to estimate the fugitive CH4 emissions released.
- Annual waste in place from Step 1 above (tons)
- Annual greenwaste, compost and biosolids used for daily cover, if applicable (tons)
- Waste characterization (percentage per waste type, default values available in Table 9.3 and Table 9.4)
- Landfill’s open year
- Landfill’s close year (if applicable)
- Fraction of CH4 in LFG from source testing (0.5 if no facility-specific value is available)
- Average annual rainfall at landfill (inches/year) to determine appropriate methane generation rate constant (k) value (See Table 9.5) The FOD model uses a series of equations to calculate the amount of CH4 generated based on the above inputs. The summary of primary IPCC FOD equations as applied by the ARB Excel tool is presented in Table 9.2.
3. Calculate fugitive emissions in metric tons of CH4 and CO2e. This calculation is completed by the FOD model.
Landfills with comprehensive LFG collection system (Chapter 9.3.2)
For the purposes of the LGOP, the LFG collection system is considered comprehensive if the system is required under US EPA’s New Source Performance Standards (NSPS), or if a more stringent system is required by a local air district. Follow the steps below to estimate the fugitive CH4 emitted by the local government’s landfill using Equation 9.1:
- Determine annual landfill gas collected
- Assess fraction of CH4 in LFG from source testing (0.5 if no facility-specific value is available)
- Determine the annual landfill gas collected for the landfill (in million standard cubic ft (MMSCF)).
- Determine the methane fraction from the annual landfill gas data collected.
- Apply a standard collection efficiency of 75%.
- Determine the methane destruction efficiency of the control device.
- Account for cover soil oxidation.
- Convert CH4 to CO2e by using a Global Warming Potential of 21 to convert metric tons of CH4 to metric tons of CO2e.
Landfills with partial LFG collection system (Chapter 9.3.3)
For the purposes of the LGOP, the LFG collection system is considered comprehensive if the system is required under US EPA’s New Source Performance Standards (NSPS), or if a more stringent system is required by a local air district. If a local government’s landfill has a partial LFG collection system in place, follow the steps below to estimate the fugitive CH4 emissions released using Equation 9.2:
- Determine annual landfill gas collected.
- Assess fraction of CH4 in LFG from source testing (0.5 if no facility-specific value is available).
- Factor to account for emissions from the uncollected surface area of the landfill.
- Determine the annual landfill gas collected for the landfill (in million standard cubic ft (MMSCF)).
- Determine the methane fraction from the annual landfill gas data collected.
- Apply a standard collection efficiency of 75%.
- Determine the methane destruction efficiency of the control device.
- Account for cover soil oxidation.
- Convert CH4 to CO2e by using a Global Warming Potential of 21 to convert metric tons of CH4 to metric tons of CO2e.
Optional reporting using surface measurements data (Chapter 9.3.4)
Some local governments directly measure and monitor fugitive CH4 emissions from solid waste facilities using a number of different methods, including static flux chambers and tunable diode laser.
The LGOP encourages landfill operators who have conducted specific site studies and estimated their fugitive emissions to report this information.
Note: This is optional. Care should be taken to not add together the optionally reported emission estimates and the emission estimates from the methodologies described previously on this page.
Local governments who have collected site-specific CH4 surface emissions can use Equation 9.3 to estimate total fugitive CH4 emissions from their landfill and report it optionally, in addition to the results from Equation 9.1 or Equation 9.2.
Note: For local governments that do not have facility-specific data to use, default values are provided for many variables.
